Reinforcement of topological gels through physical crosslinking: A coarse-grained molecular dynamics study

Slide-ring (SR) gels, characterized by slidable crosslinking sites, exhibit superior ductility and fracture toughness. However, their mechanical strength remains insufficient, limiting their practical applications. A molecular-level understanding is essential for improving the mechanical properties of SR gels. This study introduces a coarse-grained molecular dynamics method to represent 3 types of gels within a unified modeling framework. The method reveals that the maximum sliding distance serves as an upper bound, constraining the strength-ductility tradeoff in SR gels. Furthermore, a novel strategy to surpass this upper limit by incorporating physical crosslinking is proposed. Numerical simulations with varying numbers of physical crosslinking sites demonstrated that incorporating physical crosslinking sites into 75% of the SR molecules provides an optimal strength enhancement. These findings offer valuable insights into the design of strong, tough and ductile SR gels.